1. Field of the Invention
Embodiments of the present invention relate to a method of manufacturing a display device, and more particularly, to a method of manufacturing a display device capable of implementing an image such as a character or a picture image.
2. Description of the Related Art
A display device of an active matrix type includes a thin film transistor for transmitting a signal and a capacitor for holding the signal. Therefore, in order to manufacture the display device of the active matrix type, mask and process operations for manufacturing the thin film transistor and the capacitor are further required. For example, a mask for forming an active layer of the thin film transistor and the lower electrode of the capacitor, a mask for forming a gate electrode of the thin film transistor and the upper electrode of the capacitor, a mask for exposing source and drain domains, and a mask for forming a source electrode and a drain electrode are required. As a result, the manufacturing cost of the group of masks increases and the manufacturing cost also increases due to the decrease of yield caused by an added process operation.
Further, in order to increase the conductivity of the lower electrode (semiconductor) of the capacitor applied with low voltage as a display device of a charged coupled driving type is introduced for low-voltage (low power consumption) driving, a mask should further be added as injection of high-concentration ions is required. Further, since the leakage current of the thin film transistor should be minimized in order to increase luminance and resolution, as a process of injecting the ions into a channel domain is required to control threshold voltage, a mask for that should further be added. Accordingly, there is a tendency for the manufacturing cost to be further increased due to an increase in the number of masks and the addition of the process operations (photolithography process, ion-injection process, removing process, etc.).